Radio-frequency radiation safety and health: Partial-body SAR calculations in magnetic-resonance image (MRI) scanning systems

摘要

The benefits of magnetic-resonance imaging (MRI) have made it the radiological modality of choice for a great number of diagnostic procedures. Aside from some acute potential risks, such as those from aneurysm clips or certain metal objects in the patient's body or scanner environment, no adverse health effects have been associated with clinical MRI. To form images, radio-frequency (RF) magnetic fields are used to excite and detect magnetic-resonance (MR) signals from body tissues. For the common 1.5 tesla (T) and, increasingly, 3.0 Τ clinical MRI scanners, the associated RF frequencies for proton imaging at 1.5 Τ and 3.0 Τ are about 64 MHz and 128 MHz, respectively.